M2 audit: excise managed connectors and xAI media-gen tools

Managed connectors (grok.com MCP admin) removed root-and-branch:
- The managed-MCP fetch/injection pipeline is gone, including the whole
  kigi-shell-session-support crate (managed-config fetch client, gateway
  tool catalog + dispatch, header injection, refresh task), reactive
  managed re-auth, mcp_doctor's grok.com-source discovery, and the
  [managed_mcps] config surface.
- TUI: the 'Managed by grok.com' section, connectors URL/deep-link,
  Action::OpenManagedConnectors, and session_team_id are gone. Local MCP
  management (list/toggle/add/remove/auth/tools) is fully intact.
- Kept as LOCAL policy: managed-settings.json MCP allow/deny enforcement,
  the multi-source local MCP merge, folder-trust gating. PluginOrigin
  Project/User labels kept (they tag locally discovered plugin dirs).

imagine/media-gen tools (xAI image/video generation) removed:
- image_gen, image_edit, video_gen, image_to_video, reference_to_video
  implementations, registrations, ToolKind/ToolInput/Output variants
  (serde-safe), config plumbing end to end, ZDR video machinery,
  /imagine + /imagine-video commands and guidance text, the bundled
  imagine skill (added to legacy cleanup so user installs delete it),
  and the media-gen render path.
- Kept: image INPUT (paste/attach, [Image #N] meta, pdf/image fetch,
  clipboard wrap), generic media-ref rendering, and the generic tool
  401-retry machinery (tests renamed, assertions unweakened).
- deploy_app stays: it is a permanently-disabled local stub deploying
  nowhere.

121 files changed, 8 deleted. Gates: workspace check/clippy 0/0, fmt,
deny ok; suites green (tools 2554, shell 4862, tui 6608, workspace
1042). Remaining grok.com strings live only in the auth-method ids and
changelog archives (§9/M3 sweep).

crates/codegen/kigi-tools/src/attribution.rs

@@ -8,18 +8,12 @@ pub const SENT_BEARER_PREFIX_LEN: usize = 12;
 /// Which tool endpoint produced the 401.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum ToolConsumer {
-    ImageGen,
-    VideoGenStart,
-    VideoGenPoll,
     WebSearch,
 }
 
 impl ToolConsumer {
     pub fn as_str(self) -> &'static str {
         match self {
-            Self::ImageGen => "ImageGen",
-            Self::VideoGenStart => "VideoGen.start",
-            Self::VideoGenPoll => "VideoGen.poll",
             Self::WebSearch => "WebSearch",
         }
     }
@@ -95,9 +89,6 @@ mod tests {
 
     #[test]
     fn tool_consumer_as_str_stable_identifiers() {
-        assert_eq!(ToolConsumer::ImageGen.as_str(), "ImageGen");
-        assert_eq!(ToolConsumer::VideoGenStart.as_str(), "VideoGen.start");
-        assert_eq!(ToolConsumer::VideoGenPoll.as_str(), "VideoGen.poll");
         assert_eq!(ToolConsumer::WebSearch.as_str(), "WebSearch");
     }
 }